A lithium/sulfur (Li/S) battery has a theoretical capacitance being one order of magnitude higher than that of a LiFePO4 battery. However, the Li/S system is not used in many applications. Before being used in a re-chargeable lithium battery, a sulfur positive electrode should overcome the following problems: (1) sulfur has a low electrical conductivity. The size of the sulfur should be small in order to ensure a high sulfur utilization and keep a high reversible capacitance during the charge-discharge cycles. (2) The intermediate product of the charge-discharge, e.g. polysulfide, should not dissolve into the electrolyte liquid for ensuring a long cycle lifetime. (3) The electrical conductivity of the positive electrode material should be enhanced for a higher rate capability of the battery.
For solving the problems listed above, one conventional method directly coats a carbon material on a sulfur carbon electrode by wet coating. However, a layered interface between the coated carbon material and the sulfur carbon electrode will dramatically increase the impedance of the electrode.
Accordingly, a novel electrode structure for solving the above problems is still called for.